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Nine examiners can examine a certain number of answer books in 12 days by working 5 hours a day. How many hours in a day should 4 examiners work to examine twice the number of answer books in 30 days?
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- 9
- 11
- 13
- 17
Correct Option: A
Here , M1 = 9
D1 = 12
H1 = 5
W1 = 1
And M2 = 4
D2 = 30
H2 = x
W2 = 2
We know that ,
| ∴ | = | ||
| W1 | W2 |
| ⇒ | = | ||
| 1 | 2 |
⇒ H2 = 9 hours
Hence required answer = 9 hours .
